Rounds in message-passing algorithms date at least back
to their use by Arjomandi et al. [1]} as
a synchronous abstraction of time complexity. Since then, they are
omnipresent in the literature. First, the number of rounds taken by a
distributed computation is a measure of its complexity.
Such round complexity was even developed into a full-fledged
analogous of classical complexity theory by Fraigniaud et
al. [2]}. Rounds also serve as stable
intervals in the dynamic network model championed by Kuhn and
Osham [3]}: each round corresponds
to a fixed communication graph, the dynamicity following
from possible changes in the graph from round to round. Finally,
many fault-tolerant algorithms are structured in rounds,
both synchronous [4]} and asynchronous ones [5]}.
